Methods and apparatus for contingency communications

ABSTRACT

Methods and systems for contingency communication are disclosed. In one embodiment, a method for providing emergency services may be performed by a base station operating in a communication system. In an embodiment, the method for providing emergency services includes transmitting a beacon signal to indicate an emergency status to enable portable devices to operate in a stress mode. A distress signal may be transmitted by a mobile device in response to the beacon signal to the base station, wherein the distress signal carries information at least comprising user identity associated with the mobile device, geolocation of the mobile device, or biometrics of a user of the mobile device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/713,002, filed Sep. 22, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/016,092, filed Feb. 4, 2016, now U.S. Pat. No.9,773,406, issued Sep. 26, 2017, which is divisional of U.S. patentapplication Ser. No. 13/424,043, filed Mar. 19, 2012, now U.S. Pat. No.9,275,540, issued Mar. 1, 2016, which claims benefit of Provisional U.S.Patent Application No. 61/595,578, filed Feb. 6, 2012, the contents ofwhich are incorporated herein by reference in its entirety.

TECHNICAL FIELD

The disclosed embodiments relate to contingency communications such as,for example, emergency networks and systems for search and rescue.

BACKGROUND

In a natural or man-made disaster (e.g., earthquake), victims can beburied or stranded under or beneath collapsed buildings. In many cases,emergency workers encounter difficulties locating victims and rescuingthem in a timely manner. What is needed is a system that enablesemergency workers to quickly locate victims during search-and-rescueefforts during such disaster scenarios.

SUMMARY

In accordance with various embodiments of the present invention, methodsand systems for providing contingency communications are disclosed. Inone embodiment, a method for providing contingency communications may beperformed by a portable device operating in a wide area communicationsystem such as a cellular voice or data network. In an embodiment, themethod for providing contingency communications includes operating in atleast one of a plurality of modes. A stress mode may be entered from anormal mode in response to receiving a beacon signal indicating anemergency status. An indication may be provided on the portable deviceregarding the emergency status via an audio, visual, or mechanical userinterface during the stress mode. An acknowledgement signal may betransmitted in response to the beacon signal.

The foregoing is a summary and thus contains, by necessity,simplifications, generalizations and omissions of detail. Those skilledin the art will appreciate that the summary is illustrative only and isnot intended to be in any way limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be thoroughly understood from the detaileddescription given below and from the accompanying drawings of variousembodiments of the invention, which, however, should not be taken tolimit the invention to the specific embodiments, but are for explanationand understanding only.

FIG. 1 is a graphical depiction of an emergency network used for searchand rescue in a disaster.

FIG. 2 is a graphical representation of a typical portable devicecomprising major components.

FIG. 3 is a graphical depiction of (a) a mesh network of MEBS's and (b)a star connection of the MEBS's to the master MEBS.

FIG. 4 is a graphical depiction of a group of PSU's connected to a MEBSto form a cluster.

FIG. 5 is a graphical depiction of direct connection of the PSU's to themaster MEBS

FIG. 6 is a graphical representation of the TDD frame structure.

FIG. 7 is a graphical representation of the FDD frame structure.

FIG. 8 illustrates an example cellular wireless network.

FIG. 9 is a graphical depiction of spectral signals in an overlaynetwork.

FIG. 10 illustrates an example of an operational procedure forpracticing aspects of the present disclosure.

FIG. 11 illustrates an example of an operational procedure forpracticing aspects of the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Methods and apparatus for contingency communications such as, forexample, emergency networks and systems for search and rescue, aredisclosed.

In some embodiments of the invention, an emergency network may comprisemobile emergency base stations (MEBS's), portable search units (PSU's),and personal terminals (PT's). A MEB may comprise multiple communicationsystems. Furthermore, an MEB may be equipped with a synchronizationsubsystem or a location determination subsystem such as a GlobalPositioning System (GPS) receiver MEBS's may communicate with each otherover a predetermined wireless network and exchange information. Some ofthe information may be obtained from processing distress signals. A PSUmay be a device carried by a mobile rescuer or mounted on a rescuingrobot. A PSU may comprise multiple communication systems and may beequipped with a synchronization subsystem or a location determinationsubsystem. A PT may be a stand-alone device or integrated or embeddedinto a portable host device. A PT may comprise or be communicativelycoupled with various sensors that are configured or designed to sensethe surrounding environment.

In some embodiments, beacon signals and probing signals may betransmitted by a MEBS over a DL broadcast channel. The signals may berelayed or repeated by a PSU or a PT. A beacon signal may containinformation that the PT can use to perform receiving functions. Thebeacon signal may also contain messages and instructions addressed tothe PT's. A probing signal may contain a unique identification for thePT or a group of PT's. The probing signal may also contain informationto allow the PT to perform receiving functions, or messages andinstructions for the PT. Distress signals may be transmitted by PT's onUL channels to a MEBS or a PSU. Distress signals may be relayed orrepeated by a PT. A distress signal may contain essential data about itsbearer. A beacon signal, probing signal, or a distress signal may occupya frequency band designated for search and rescue during emergencystate, or may occupy or overlay on a frequency band used by a normalradio network.

Beacon signals may be periodically broadcast by MEBS's via the DLchannel, and the PT's may respond to the beacon signal by transmittingtheir distress signals via the UL channels in a manner as instructed bythe beacon signals. When MEBS's successfully detect the distress signalsover the UL channels, the MEBS's may proceed to decode the informationcarried by the disaster signals, extract the attributes associated withthe disaster signals, and report the data and information associatedwith the PT's to the master MEBS. The master MEBS may combine the dataand information to determine the PT's complete identifications,locations, biometrics, and priority levels for rescue operations.

The following discussion contemplates the application of the disclosedtechnology to communication systems, communication networks, wirelesslocal area networks, wireless ad hoc networks, time division duplex(TDD) networks, frequency division duplex (FDD) networks, wirelessmobile terminals, and wireless base stations.

The following description provides specific details for a thoroughunderstanding of, and enabling description for, various embodiments ofthe technology. One skilled in the art will understand that thetechnology may be practiced without these details. In some instances,well-known structures and functions have not been shown or described indetail to avoid unnecessarily obscuring the description of theembodiments of the technology. It is intended that the terminology usedin the description presented below be interpreted in its broadestreasonable manner, even though it is being used in conjunction with adetailed description of certain embodiments of the technology. Althoughcertain terms may be emphasized below, any terminology intended to beinterpreted in any restricted manner will be overtly and specificallydefined as such in this Detailed Description section. Further, those ofordinary skill in the relevant art will understand that they canpractice other embodiments of the disclosure without one or more of thedetails described below. Finally, while various methods are describedwith reference to steps and sequences in the following disclosure, thedescription as such is for providing a clear implementation ofembodiments of the disclosure, and the steps and sequences of stepsshould not be taken as required to practice this disclosure.

It should be understood that the various techniques described herein maybe implemented in connection with hardware or software or, whereappropriate, with a combination of both. Thus, the methods and apparatusof the disclosure, or certain aspects or portions thereof, may take theform of program code (i.e., instructions) embodied in tangible media,such as floppy diskettes, CD-ROMs, hard drives, or any othermachine-readable storage medium wherein, when the program code is loadedinto and executed by a machine, such as a computer, the machine becomesan apparatus for practicing the disclosure. In the case of program codeexecution on programmable computers, the computing device generallyincludes a processor, a storage medium or other memory readable by theprocessor (including volatile and non-volatile memory and/or storageelements), at least one input device, and at least one output device.One or more programs that may implement or utilize the processesdescribed in connection with the disclosure, e.g., through the use of anapplication programming interface (API), reusable controls, or the like.Such programs are preferably implemented in a high level procedural orobject oriented programming language to communicate with a computersystem However, the program(s) can be implemented in assembly or machinelanguage, if desired. In any case, the language may be a compiled orinterpreted language, and combined with hardware implementations.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” Words using the singular or pluralnumber in this Detailed Description section also include the plural orsingular number respectively. Additionally, the words “herein,” “above,”“below”, and words of similar import, when used in this application,shall refer to this application as a whole and not to any particularportions of this application. When the claims use the word “or” inreference to a list of two or more items, that word covers all of thefollowing interpretations of the word: any of the items in the list, allof the items in the list and any combination of the items in the list.

Emergency Networks Components

FIG. 1 illustrates a scenario where an emergency network is deployed forsearch and rescue. The components of an emergency network 100 mayinclude mobile emergency base stations (MEBS's) 102, portable searchunits (PSU's), and personal terminals (PT's).

MEBS

A MEBS 102 may be mounted on a land vehicle, airborne craft, or marinevessel. A MEBS may also be set up at a fixed location such as a hill-topor a tower site of an existing/traditional/normal radio network. Withoutloss of generality, MEBS is used in the ensuing paragraphs to illustratefunctions of either a fixed or mobile base station.

The vehicle that a MEBS is mounted on may also serve as a local commandpost. The mounted MEBS may communicate with a command center or anyfacility outside of the emergency network via a communication system ornetwork such as a communication satellite, a point-to-point microwavesystem, or/and a cellular wireless network.

A MEBS may consist of multiple communication systems. Furthermore, itmay be equipped with a synchronization or location determinationsubsystem, such as a Global Positioning System (GPS) receiver. MEBS'smay communicate with each other over a specific wireless network andexchange information obtained from processing distress signals. A MEBSmay communicate with a PSU via a specific wireless network, exchanginginformation with and providing instruction to the PSU. A MEBS maytransmit the beacon or probing signals to PT's and receive distresssignals from PT's.

PSU

A PSU can be carried by a mobile rescuer or mounted on a rescuing robot.A PSU may consist of multiple communication systems and may be equippedwith a synchronization or location determination subsystem, such as aGPS receiver. A PSU may communicate with a MEBS via a specific wirelessnetwork. A PSU may also transmit beacon or probing signals to PT's andreceive distress signals from PT's. In some embodiments, a PSU may beconsidered a portable MEBS and may implement similar functions.

PT

A PT can be a stand-alone device or integrated or embedded into aportable host device such as a cellular phone, personal data assistant(PDA), tablet computer, iPhone, iPad, smart phone, portable mediaplayer, portable game player, and watch. A PT can also be a part ofintegrated circuitry in a host device or be a set of software code thatruns on a host device (or portable device). The host device may becarried by or in the vicinity of a person. A typical portable device200, shown in FIG. 2, may comprise processors for normal-mode operations202 204 and a processor for stress-mode operation 210, as well as othermajor components. The stress-mode processor 210 may be coupled directlyor via a data bus with the normal-mode processors 202 204 and othermajor components. The operation of the stress-mode processor 210 may beindependent of the operations of the normal processors 202 204. Thestress-mode processor 210, when entering into the stress mode, may takecontrol of the operations of the major components. For example, it mayactivate some components while shutting down others.

A PT may consist of or be coupled with various sensors including, butnot limited to, motion sensing, orientation sensing, audio sensing,optical sensing, pressure sensing, temperature sensing, chemicalsensing, biological/physiological sensing, and/or biometric sensing. Thesensors may be configured or designed to sense the surroundingenvironment. For example, a PT may also be equipped with multiple audioor video sensors that can sample audio or video from different angles ordirections. These sensors may be configured or controlled by theemergency network or a normal radio network to obtain better results.The operation can help rescue team to better observe and understand thedisaster environment, for example, inside a collapsed building.

In some embodiments, a sensor or sensors on a PT may be designed toprovide a wide angle view of the surrounding environment. For example,an optical sensor may be in the form of a fish eye having a 360-degreeview. A part of the PT containing a sensor or sensors may pop up fromthe host device to survey the environment. A sensor may have a shape ofpolyhedron, such as a cube or octahedron, with sensing capability oneach side or multiple sides to provide a full or near full view of theenvironment.

A PT may be configured to receive the beacon or probing signals from oneor more MEBS's and PSU's and transmit distress signals to one or moreMEBS's and PSU's.

A PT may comprise both receiving circuitry and transmitting circuitry.The receiving circuitry may be further divided into two parts. The firstpart may perform the function of detecting beacon or probing signals andthe second part may perform other receiving functions such asdemodulation and decoding.

In some embodiments, the detection circuitry may be kept powered oncontinuously, turned on for a period and off for another period ofdifferent lengths, or turned on and off under predetermined conditions.In an embodiment, the detection circuitry may be turned on

1. when its host device has not received the normal and/or expectedwireless signals (e.g., GSM, HSPA, and LTE) for a specified period oftime;

2. when its host device senses that there has been no movement for apredetermined period of time, that it is under some form of physicalpressure, or/and that its carrier is under certainbiological/physiological stresses; or

3. when instructed by a host device that receives instruction of anormal radio network. For example, a normal radio network may inform thehost device and therefore a PT how often it should check/detect a beaconsignal potentially transmitted from a MEBS. The period may beconfigurable by the normal radio network or emergency network.

When its host device is turned off, the PT detection circuitry may bekept functioning using one of the methods described above.

Once a PT receives a beacon or probing signal from a MEBS or PSU thatindicates an emergency state, the PT may enter into a stress mode.

When the detection circuitry detects beacon/probing signals, the rest ofthe receiving circuitry may be turned on to perform the necessaryreceiving functions.

The transmitting circuitry may be turned on when the PT is ready orscheduled to transmit distress signals to the MEBS's or PSU's. Aftertransmission, the transmitting circuitry may be turned off until it isready or scheduled to transmit again.

The PT may also perform the following functions:

1. The PT alerts its carrier of the ongoing rescuing effort throughaudio or/and visual messages.

2. The PT sends out audio or/and visual messages to comfort andencourage its earner.

3. The PT turns off the normal functions of the cell phone, PDA, orplayers to save power.

In some embodiments, the host device can be powered by at least twobatteries, one reserved for performing normal functions such as phonecalls and the other for the PT operations. Alternatively, the hostdevice may reserve a minimum level of power for performing the PTfunctions and any power exceeding that level can be used for carryingout general applications. Some functions of the PT can be overriddenmanually.

Emergency Network

An emergency network may be formed between the MEBS's, PSU's and PT's. AMEBS within the emergency network may serve as the master MEBS, whichprovides a reference that all other MEBS's, all PSU's and PT's cansynchronize to. An emergency network, including MEBS's, PSU's, and PTs,may operate at a low frequency band for deep in-building penetration. AMEBS may cover a large area with a high level of transmission power.

The emergency network may consist of multiple systems that enablecommunications between MEBS's, PSU's, and PT's.

The MEBS's 302 may form a mesh network and exchange information witheach other, as depicted in FIG. 3a . Alternatively, a MEBS onlycommunicates with the master MEBS 304, as depicted in FIG. 3 b.

A group of PSU's 404 may be associated only with a particular MEBS 402to form a cluster 406, as depicted in FIG. 4. The MEBS directlycommunicates with its PSU's to provide coordination and instructions.Alternatively, PSU's 502 may be directly associated with the master MEBS504, which directly communicates with the PSU's 502 to providecoordination and instructions, as depicted in FIG. 5.

In one embodiment, a MEBS may receive data from a normal radio networkthat was or is running in the neighborhood of disaster area. The datamay include information about subscribers that are registered on,associated with, or resided within, whether actively or inactively, thenormal radio network. The MEBS utilizes the information to assist itssearch and rescue functions.

An emergency network may be used in parallel with a normal radio networkor in place of a normal radio network if the latter has collapsed duringa disaster.

Signal Formats and Structure

Beacon signals may be transmitted by a MEBS over a DL broadcast channel.The beacon signals may be relayed or repeated by a PSU or a PT. A beaconsignal may contain information for the PT to perform receiving functions(e.g., synchronization in time and frequency, and channel estimation)and messages and instructions to the PT's (e.g., UL multiple access andcontrol, and acknowledgement of reception of distress signals).

Probing signals may be transmitted by a MEBS or PSU to an individual PTor a specific group of PT's. A probing signal may contain the uniqueidentification of the PT or the group of PT's. The probing signals maybe relayed or repeated by a PT. A probing signal may contain informationfor the PT to perform receiving functions (e.g., synchronize in time andfrequency, and channel estimation) and messages and instructions to thePT (e.g., UL multiple access and control, and acknowledgement ofreception of distress signals).

A beacon signal or probing signal may be shaped to provide thecapability to penetrate structures in a disaster environment, such ascollapsed buildings. In one embodiment, a beacon signal or a probingsignal may be a spread-spectrum signal with high spreading gain orcoding gain.

Distress signals may be transmitted by PT's on UL channels to a MEBS ora PSU. The distress signals may be relayed or repeated by a PT. Adistress signal may contains essential data about its carrier, such asthe carrier's biometrics (or life signs: temperature, heart beats, bloodpressure, movement, key pressing, etc.), its location (e.g., from GPS),carrier's identification, and other data. A distress signal may containpilot signals to assist the MEBS or PSU with signal reception.

A beacon signal, probing signal, or a distress signal may occupy afrequency band designated for search and rescue during an emergencystate or may occupy or overlay on a frequency band used by a normalradio network.

TDD

In the time-division-duplex (TDD) case, a transmission frame 600consists of two subframes, one for DL transmission 602 and the other forUL transmission 604, as depicted in FIG. 6. It should be noted here thatthe term “frame” is only a time unit of a specific duration. It is usedfor better understanding and illustration of the methods and processes.Following a DL subframe, there is a relatively short time periodprovided as guard time for transition from DL to UL and following a ULsubframe, there is another relatively short time period provided asguard time for transition from UL to DL. A UL subframe may besubstantially longer than the DL subframe.

DL subframe 602 may be divided into multiple DL slots 606. One or moreslots may be assigned for transmission of beacon signals 610 by theMEBS's. One or more slots may be used for retransmission or relay ofbeacon signals 612 by a MEBS, PSU, or/and PT. One or more slots may beassigned for transmission of probing signals 614 or probing relay 616 bya MEBS or PSU. One or more slots may be allocated for the use by theMEBS and PSU's in a cluster 618.

UL subframe 604 may be divided into multiple UL slots 608. One or moreslots may be assigned for transmission of distress signals 620 by thePT's. One or more slots may be used for retransmission or replay ofdistress signals 622 by a PSU or/and PT. A UL slot is not necessarily ofthe same length as a DL slot.

FDD

In the frequency-division-duplex (FDD) case, DL transmission and ULtransmission are carried out in two different frequency bands. A bandfor UL transmission may be substantially wider than that for DLtransmission. An FDD transmission frame 700 consists of multiple slots,as depicted in FIG. 7.

In some embodiments, the frame length is the same for both the DL andUL, but a UL slot does not necessarily have the same length as a DLslot, as long as the following condition is met:

L _(DL) ·M=L _(UL) ·N

where L_(DL) denotes the length of a DL slot and L_(UL) denotes thelength of a UL slot, and M and N are positive integers.

In other embodiments, the DL frame length may be different from the ULframe length. One or more DL slots 702 may be assigned for transmissionof beacon signals 704 by the MEBS's. One or more slots may be used forretransmission or replay of beacon signals 706 by a MEBS, PSU, or/andPT. One or more slots may be assigned for transmission of probingsignals 708 or probing relay signals 710 by a MEBS or PSU. One or moreslots may be allocated for the use by the MEBS and PSU's in a cluster712.

One or more UL slots 714 may be assigned for transmission of distresssignals 716 by the PT's. One or more slots may be used forretransmission or relay of distress signals 718 by a PSU or/and PT.

Multiple Access

DL Transmission

Multiple MEBS's may transmit or retransmit the same beacon signal atsubstantially the same time and over the same frequency channel.

Multiple PSU's and PT's may relay the same beacon signal atsubstantially the same time and over the same frequency channel.

The master MEBS may provide schedules to other MEBS's and PSU's tocoordinate the transmission of probing signals. The scheduling may bebased on a first-come-first-service policy for theprobing-signal-sending requests by the MEBS's and PSU's or based on apriority set by a predefined set of criteria. For example, a higherpriority may be given to the MEBS or PSU that is to probe a PT ofcritical biometrics or low battery levels.

UL Transmission

A UL channel may consist of multiple subchannels in time, frequency,code, or a combination thereof. UL multiple access can be provided usingTDMA (time division multiple access), FDMA (frequency division multipleaccess), CDMA (code division multiple access), CSMA (carrier sensemultiple access), etc.

Unlike in a traditional cellular network where mobile devices enter thenetwork gradually (instead of joining network in a burst), a largenumber of PT's may respond to a beacon signal in a burst. Therefore, itis important to design the initial uplink signaling, e.g., randomaccess, to avoid frequent collisions of uplink signals.

In some embodiments, the beacon or probing signals may contain messagesfor UL multiple access instructions for the PT's. The message mayinstruct a group of PT's with certain common attributes to transmittheir distress signals at specific UL slots, using specific codes,or/and via specific subchannels in the time, frequency, or code domains,or a combination thereof. The common attributes may be the physicalcharacteristics or the identifications of the PT's. For example, a groupPT's may have the same last hex number in the MAC address or the lasttwo digits of their identification may fall within a specified range.The assignment of slots, codes, or subchannels to the PT's can be in aparticular order, in a random order, or other prescribed means. Anassignment example is given in the table below.

Attribute Slot # Subchannel # Code # xxx01 1 1 1 xxx02 1 1 2 . . . 1 1 .. . xxx10 1 1 10  xxx11 2 1 1 . . . 2 1 . . . xxx20 2 1 10  . . . . . .. . . . . . xxx97 m N 7 xxx98 m N 8 . . . . . . . . . . . .

In an embodiment, the UL multiple-access instruction may contain thepriority for the UL transmission of distress signals based on thereceived signal strength or SNR (signal-to-noise ratio) of the DLsignals, the remaining battery level of the PT's, the biometrics of thePT carriers, or other criteria.

In one embodiment, the MEBS can access a database that maps theidentities of users/subscribers residing on traditional/normal cellularnetworks and the identities of PT's. The MEBS may utilize theinformation it obtains from the data base about residing users (e.g.,the identities in the neighborhood) to instruct the PTs regardingmultiple access. For example, the MEBS can divide the residing users andcorresponding PTs into a plurality of groups and assign different radioresources for different groups for random access or sending distressedsignals.

Network Overlay

In some embodiments of the invention, the emergency network may beoverlaid temporally and locally, on top of an existing/normal radionetwork or cellular wireless network for non-emergency-applications(e.g., audio broadcast, TV broadcast, and land mobile radio).

Referring to FIG. 8, in a normal cellular wireless network, thegeographical region to be serviced by the network is normally dividedinto smaller areas called cells 800. In each cell 800, coverage isprovided by a base station (BS) 804. Thus, this type of structure isnormally referred to as a cellular structure, as shown in FIG. 8. Withineach coverage area, there are located mobile stations (MS's) 808 to beused as an interface between the users and the network. BS 804 isconnected to the backbone of the network, usually by a dedicated link.Base station 804 also serves as a focal point to distribute informationto and collect information from its mobile stations by radio signals. Acell can also be divided into sectors 806. From a system engineeringpoint of view each sector can be considered a cell. In this context, theterms “cell” and “sector” are interchangeable.

For a wireless network using multicarrier transmission scheme, such asorthogonal frequency division multiplex (OFDM), the physical mediaresource (e.g., radio or cable) can be divided in both the frequency andtime domains. This division provides high flexibility and finegranularity for resource sharing.

One or more normal channels allocated for the existing radio network canbe converted and aggregated into a broadcast channel for transmittingthe beacon or probing signals by the MEBS's and PSU's. Normal channelsmay be those used in normal (non-emergency) applications, such ascommercial radio/TV broadcasting or land mobile communications.

The distress signal transmitted by a PT may be spread across theavailable spectrum or a spectrum substantially wider than the broadcastchannel for the beacon and probing signals. Spectral valleys created inthe overlaid signal to reduce interference with the broadcast channel orother channels may also be used, as shown in FIG. 9

The spectral nulls can be achieved either by filtering in the timedomain or by suppressing some subcarriers in the frequency domain.

In other embodiments, normal channels used by an existing/normal networkcan be vacated for use by the emergency network. A MEBS or a PT mayoperate in the same frequency band as used by a normal radio networkemploying a 2G, 3G, or 4G technology such as GSM, WCDMA, or LTE. In-bandsignaling may be used for the emergency network. Alternatively, theemergency network may operate in a frequency band different fromoperation frequency bands of a normal radio network.

An existing/normal radio network can temporally, partially, and/orlocally be reconfigured or switched to emergency operation mode. Forexample, a group of the base stations in a disaster zone may bereconfigured or switched by the network operator to serve as MEBS's.These base stations may transmit or retransmit the same beacon signal oremergency signal at substantially the same time using the same frequencychannels.

In some embodiments, an LTE system can be reconfigured into a search andrescue system In the downlink, the primary synchronization signal (PSS),the secondary synchronization signal (SSS), and/or the physicalbroadcast channel (PBCH) may be repeated in multiple, preferablyconsecutive, OFDM symbols to increase SNR and penetration.Alternatively, the bandwidth for the PSS, SSS, and PBCH may be widenedby increasing the length of a Zadoff-Chu sequence or by repeating aZadoff-Chu sequence in the frequency domain. Similarly, in the uplink, arandom access signal or a sounding reference signal (SRS) may berepeated in the time domain (e.g., multiple, preferably consecutive,OFDM symbols or time slots). Alternatively, the bandwidth for the randomaccess signal or SRS and the PBCH may be widened by increasing thelength of a Zadoff-Chu sequence or by repeating a Zadoff-Chu sequence inthe frequency domain.

Communications Between MEBS's

The communications between MEBS's may make use of an existing datacommunication protocol. Information sent by a MEBS to another MEBS mayinclude its own location coordinates, the partial or completeidentification of a PT, the PT's location coordinates, the correspondingbiometrics, or/and the attributes of the corresponding distress signal(e.g., angle-of-arrival and time-of-arrival).

In an embodiment, a MEBS may send a request for transmission of probingsignals to the master MEBS, which in return provides the schedule forthe MEBS to transmit the probing signals.

Communications Between MEBS's and PSU's

The communications between MEBS's and PSU's may make use of an existingdata communication protocol. Information sent by a MEBS to a PSU or viceversa may include its own location coordinates, partial or completeidentification of a PT, the PT's location coordinates, the correspondingbiometrics, or/and the attributes of the corresponding distress signal(e.g., angle-of-arrival and time-of-arrival).

In an embodiment, a PSU may send a request for transmission of probingsignals to the master MEBS, which in return provides the schedule forthe PSU to transmit the probing signals.

Operations

Beacon signals may be periodically broadcast via the DL channel. A MEBSmay transmit the beacon signals using a wide antenna beam in a PT-sparsearea or by scanning through a PT-dense area using a narrow antenna beam

The PT's may respond by transmitting their distress signals via the ULchannels in a manner as instructed by the beacon signals. If a PT isequipped with a GPS receiver or other location determination capability,the PT may include its latest coordinates in the distress signal. Inaddition, the MEBS or PSUs may seek to locate the PT through detectionof arrival time or receiving power of the distress signal transmittedfrom the PT. Multiple MEBS or PSUs at different locations may work incollaboration to locate the PT.

In one embodiment, once a PT receives a beacon or probing signal thatindicates a disaster state, the PT may enter into a distress state andautomatically transmit a distress signal. The PT may also inform orcontrol the host device to enter into a power saving mode for extendedbattery life by turning off non-essential functions that consume power.For example, the host device may terminate processes for entertainmentfunctions, such as video-rich operations or large file downloading, thatconsume a large amount of power.

Upon the detection of a beacon signal, a PT or its host device may fallback from an advanced communication operation to a rudimentary operation(e.g., from LTE to 3G or GSM or from 3G to GSM) for reducing powerconsumption.

In one embodiment, a host device may comprise a special man-machineinterface for human initiation of transmitting distress signals, with orwithout reception of a beacon signal, from the MEBS or PSU. For example,a host device may have a special button or an icon on its display screenthat a human can push/touch to activate sending a distress signal. Theinformation contained in the distress signal may be automaticallygenerated or configured by network or by the carrier/operator of thehost device.

A PT may return to a normal state after it receives a signal from MEB S,its host device receives an instruction from the traditional/normalradio network, or by human interaction.

MEBS's may detect the distress signals over the UL channels. Once adistress signal from a PT is detected successfully by a MEBS, the MEBSmay proceed to decode the information carried by the signal and toextract the attributes associated with the signal. The MEBS may thenreport the data and information associated with this PT to the masterMEBS, which may combine the data and information from other MEBS's todetermine the PT's complete identification, its location, biometrics,and its priority for rescue. The master MEBS may then register the PTwith the corresponding data and registry information. The registry,which is maintained by the master MEBS, may be a table consisting ofentries of the identification of the PT, its location, its biometricsinformation, its priority for rescue, and its rescue status. Once the PThas been registered, an acknowledgement message is embedded in a beaconsignal to be transmitted by the MEBS's. The master MEBS may periodicallysend the updated registry to MEBS's.

Once a PT has received the acknowledgement, the PT may be configuredsuch that it will not transmit the distress signal even if it belongs toa group that a beacon signal calls for to transmit. The PT remainssilent until it is probed by a MEBS or PSU with a probing signal. ThosePT's that have not received the acknowledgement will continue to listento the beacon signal for instructions to retransmit their distresssignals.

Based on the information in the registry, a MEBS may determine if itwill instruct its PSU's to act. For example, if the PT is located withinthe coverage area of a particular MEBS with high priority, this MEBSwill dispatch one of its PSU's to approach the PT and to pinpoint itsexact location for rescue.

The PSU may transmit a probing signal by pointing its high-directivityantenna toward the direction of the PT. Once the PT hears the probingsignal, it will respond by transmitting a distress signal. Based on thedistress signal, the PSU may find the exact location of the PT for therescue. There are a number of ways to determine the status of theperson/owner associated with this PT. If the PT signal level increasessignificantly or if the location of this PT changes significantly, it islikely that the person/owner has been found and the PSU may report therescue status. The status can also be reported manually.

To distinguish a PT of a disaster victim from a non-victim, certaincriteria can be applied. For example, if the speed of the movement of aPT is above a specified threshold and/or its range of movement isgreater than a specified threshold, it may be considered unlikely thatthis particular PT is carried by a disaster victim

When an overriding input (e.g., a key sequence, voice command, orgesture) is entered by its carrier, the PT may be configured so that itwill not respond to the beacon or probing signal and/or send a signal toindicate that this PT is carried by a non-victim

In some embodiments, a MEBS or a computer server connected to one ormore MEBS may receive and store information for users that have residedor currently reside in one or more traditional/normal radio networksthat provide data or voice service to subscribers in the sameneighborhood. The normal radio networks may be operated by differentservice providers, with possibly different technologies. For example,one service provider/operator may use GSM technology, while anotherservice provider/operator may use a CDMA technology. Some or all of themobile devices serviced by an operator may contain one or more PTs. TheMEBS may transmit beacon signals or probing signals to PTs and detectfeedback signals such as distressed signals transmitted from PTs. TheMEBS or the computer server may then compare the list of users thatresided on normal radio networks (before a disaster), the list ofresponding PTs, and/or the list of users that are identified throughother methods, e.g., bulletin board, manual check-in, or hospitalreports. The results of the comparison results may be used to directsearch and rescue efforts.

As an example, consider a person with a mobile device that was residingon a normal radio network in a neighborhood, the mobile device beingequipped with a PT. The MEBS receives a distress signal from the PT overthe emergency network. If the person is located or identified, then theperson is marked as located in the user list maintained by the MEBS orthe computer server. If a user in the list is still marked missing, amessage may be sent over the emergency network to request manualfeedback from the user, either through voice, video, or the datainterface. A key function or touch screen function may be pre-configuredfor easy operation by the person (possibly severely wounded) to sendfeedback. Alternatively, the sensors in the PT or mobile device mayautomatically or remotely controlled to detect or record any vital signssuch as sound, temperature, or pulses, record audio signals via itsmicrophone, or record a video signal via its camera sensor. The PT ormobile device may then automatically or be remotely commanded totransmit the signals related to the recorded signals, audio signals, orvideo signals (possibly with compression and encoding) to the MEBS. Theabove actions may be conducted repeatedly to improve results.

The data received from the PT and/or location information obtained viathe emergency network may be provided to rescue teams to improve searchand rescue efforts. If one or more normal radio networks are stillfunctioning after a disaster, these normal radio networks and theemergency network can collaborate to provide better results.

In some embodiments, a PT may have three operation modes: normal mode,semi-stress mode, and stress mode. A PT in normal mode may enter intosemi-stress mode based on one or more conditions, such as loss (suddenor for an extended period) of normal radio network signals. A PT innormal or semi-stress mode may enter into stress mode after detection ofa beacon signal indicating an emergency state from a MEBS or PSU, orafter input from human interaction. On the other hand, based on humaninteraction or input, a PT may change modes from stress mode orsemi-stress mode to normal mode. A PT may be configured to functiondifferently in different modes. For example, a PT in semi-stress modemay increase the frequency of wake-up for detection of beacon signalsfrom MEBS. A PT in the stress mode may automatically configure itsresiding mobile device into power saving mode to extend battery life.

In other embodiments, a MEBS may have two operational modes: normal modeand stress mode. In normal mode, a MEBS may broadcast beacon signalsindicating a normal environment and receive or detect signals from PTsseeking special help. In stress mode, a MEBS may broadcast beaconsignals indicating an emergency state and receive or detect stresssignals from PTs.

FIG. 10 depicts an exemplary operational procedure for providingcommunications including operations 1000, 1002, 1004, 1006, and 10008.In one embodiment, the procedure may be performed by a portable deviceoperating in a wide area communication system such as a cellular voiceor data network.

Referring to FIG. 10, operation 1000 begins the operational procedureand operation 1002 illustrates operating in at least one of a pluralityof modes. In an embodiment, the plurality of modes includes a normalmode and a stress mode. In another embodiment, the plurality of modesincludes a semi-stress mode. In one embodiment, the portable device mayenter the stress mode from the normal mode in response to a user inputreceived via a user interface on the portable device. Additionally, andoptionally the portable device may enter the normal mode from the stressmode in response to the user input.

In one embodiment, the portable device may enter the semi-stress modefrom the normal mode in response to the portable device losing itsconnection to a cellular voice or data network. Furthermore, theportable device may increase the frequency with which it detects thebeacon signal in the semi-stress mode, as compared to the frequency withwhich it detects the beacon signal in the normal mode.

In one embodiment, the portable device may operate in the stress modewith a battery physically or operationally separate from a battery foroperation in a normal mode.

In one embodiment, the portable device may operate in the stress modewith less power than in the normal mode. The portable device may alsofall back from an advanced communication operation to a rudimentaryoperation in response to entering the stress mode. For example, theportable device may fall back from LTE or 3G operation to GSM operationupon entering the stress mode

Operation 1004 illustrates entering the stress mode from the normal modein response to receiving a beacon signal indicating an emergency status.

Operation 1006 illustrates providing an indication on the portabledevice of the emergency status via an audio, visual, or mechanical userinterface during the stress mode.

Operation 1008 illustrates transmitting an acknowledgement signal inresponse to the beacon signal. In one embodiment, the acknowledgementsignal may indicate information selected from a group comprising:identity of the portable device, position of the portable device, andbiometrics of the user or carrier of the portable device. The portabledevice may also receive a scheduling signal containing informationindicating instructions for transmitting the acknowledgement signal.

In some embodiments, a user or carrier of the portable device may beprompted to report the user or carrier's safety or medical status.Furthermore, the portable device may transmit a stress signal inresponse to determining that a time out indicating failure to receiveuser input has exceeded a predetermined value.

In an embodiment, the portable device may further receive and act uponan instruction to activate a monitoring device on the portable device.

FIG. 11 depicts an exemplary operational procedure for providingcommunications including operations 1100, 1102, 1104, and 1106. In oneembodiment, the procedure may be performed by a base station in anetwork comprising base stations and portable devices. The network maybe, for example, a wide area communication system such as a cellularvoice or data network.

Referring to FIG. 11, operation 1100 begins the operational procedureand operation 1102 illustrates transmitting a beacon signal indicatingan emergency status to a portable device. In one embodiment, the beaconsignal may be usable by the portable device to determine whether toenter a stress mode. In an embodiment, the beacon signal may generate tofacilitate in-building penetration of the transmitted beacon signal. Forexample, the beacon signal may be a spread-spectrum signal with highspreading gain or coding gain.

In some embodiments, the acknowledgement signal may carry informationthat may comprise the identity of the portable device, the position ofthe portable device, and/or biometrics of a carrier or user of theportable device.

Operation 1104 illustrates receiving an acknowledgement signal from theportable device in response to the beacon signal.

Operation 1106 illustrates deriving from the received acknowledgementsignal information associated with the portable device or a carrier ofthe portable device.

In an embodiment, the base station may also transmit an instruction toactivate a monitoring device on the portable device. In otherembodiments, the base station may transmit a scheduling signalcontaining information indicating instructions for transmitting theacknowledgement signal. In further embodiments, the base station mayaccess a database or a list of subscribers of a cellular networkcovering a geographical area near or overlapping with a geographicalarea covered by the base station.

Lastly, while the present disclosure has been described in connectionwith the preferred aspects, as illustrated in the various figures, it isunderstood that other similar aspects may be used or modifications andadditions may be made to the described aspects for performing the samefunction of the present disclosure without deviating there from Forexample, in various aspects of the disclosure, methods and systems forcommunicating in a wireless communications system were disclosed.However, other equivalent mechanisms to these described aspects are alsocontemplated by the teachings herein. Therefore, the present disclosureshould not be limited to any single aspect, but rather construed inbreadth and scope in accordance with the appended claims.

What is claimed:
 1. A method for providing communication by a basestation in a network comprising base stations and portable devices, themethod comprising: transmitting a beacon signal indicating an emergencystatus to a portable device, the beacon signal usable by the portabledevice to determine whether to enter a stress mode; receiving anacknowledgement signal from the portable device in response to thebeacon signal; and deriving, from the received acknowledgement signal,information associated with the portable device or a user of theportable device.